Leak resistant drinking cups are often adapted for use by young children (e.g., infants, toddlers, preschoolers) or people on the go (e.g., commuters, students, hikers, joggers). Usually, the cup includes a container defining an interior space for receiving and holding liquids therein. The container typically includes an open top, and the cup often includes a relatively rigid cover for closing the open top of the container. The cover can be releasably attached (e.g., snapped or screwed on) to the container. These types of drinking cups are often configured so that when they are turned over, liquid inside the cup is inhibited from spilling out of the cup by a valve or valve assembly.
The valve or valve assembly is typically disposed between the cover and the container and can be configured from a sealed configuration for inhibiting liquid from passing out of the drinking cup to an unsealed configuration for allowing liquid to pass out of the cup for drinking. Most commonly, the valve is actuated by suction (i.e., vacuum, negative pressure) applied by the user to the interior of the cup by sucking on a part of the drinking cup (e.g., a spout, a straw). The applied vacuum pressure causes the valve to move or otherwise deform in such a way that a path past the valve is created so liquid can flow out of the cup. It is possible that the valve might be actuated in other ways, such as a purely mechanical actuation. But for young children, vacuum pressure actuation is often most preferable because the only time the valve is open is when the child is in the act of taking a drink.
Vacuum actuated drinking cups of the type just described must balance the need to assure positive sealing with the need to make the cup easy to use. A strong seal by the valve requires greater vacuum to open, making it difficult for the user to use. A valve having a seal that requires a lower vacuum to open may not seal sufficiently tight to prevent at least some liquid flowing past it, especially when dropped, swung, shaken, or impacted. As a result, valves having low vacuum actuated seals are often more prone to leak. Moreover, typical valves or valve assemblies include slits (or cuts) in the valve or valve assembly that allow liquid to flow through the valve or valve assembly during use of the cup. However, these slits often provide a pathway for liquid to potentially leak from the cup.
Frequently, conventional valves are relatively small and, as a result, often require a substantial vacuum to actuate because the pressure acts on only a relatively small area of the valve. In other words, the user has to suck with significant effort to get the valve to open and obtain a drink, which makes the cup less desirable to the child.
Often, the valve or valve assembly can be disassembled from the cover for cleaning. Some valves and valve assemblies are difficult to detach and reassemble as they require precise alignment or orientation of relatively small parts or parts with small tolerances. Moreover, small valves or pieces of a valve assembly may be easily lost and are often difficult to handle.
There remains a need for a valve assembly and a leak resistant straw cup with a valve assembly that effectively inhibits liquid from leaking from the cup but can be readily actuated when subjected to vacuum applied by a user.